Noncongealing oil cooler construction



0d. 29, 1946. c PERKINS 2,410,180

- NONCONGEALING OIL COOLER CONSTRUCTION.

Filed Oct. 1, 1942 2 Sheets-Sheet 1 IN VEN TOR.

cizbzrleaffe rbm BY 2Q t Oct. 29, 1946. c. T. PERKINS 2,410,180

'NONCONGEALING OIL COOLER CONSTRUCTION Filed Oct. 1, 1942 2 Sheets-Sheet 2 IN VEN TOR.

26 C/lzzrlea fi erh'na,

Patented Oct. 29, 1946 NONCONGEALING on. COOLER CONSTRUCTION 4 Claims. 1

The present invention relates to a new and novel arrangement of tubes and fins and more specifically is directed to the introduction of additional thermal members in combination with the tubes and fins which will aid in conducting heat from tub-e to tube for the prime purpose of inducing the flow of fluid that may be congealed in the tubes. The device of the present inventio'nfisparticularly devised for the purpose of quickly and eiliciently causing a flowage of oil in a core member of an oil cooler wherein the oil has become congealed due to low temperatures whenever such core or cooler has been standing idle.

Many of the practical units of present day construction of oil coolers are being fabricated from steel, Monel metal, Cupro nickel, and other low thermal conductivity metal to withstand pressures, but such oil coolers present the further problem of limited heat conductivity between the various tubes carrying oil and wherein certain of the tubes might become thawed out while certain of the outer or the more exposed tubes may never fully reach a temperature for the oil to break through so as to allow the proper and efficient functioning of an oil cooler in its designed capacity. It has been found that most of the existing oil coolers will function properly and efficiently at temperatures ranging from 32 Fahrenheit to between 200 and 300 Fahrenheit. In these devices, in order to obtain an efiicient heat transfer it has been the practice to use Various devices in obtaining exceptional heat transfer ability in moderate or high temperatures. Such devices may encompass an assortment of methods which are well known in the practice and by those skilled in the art, many of such items incorporating exceptionally thin, fiat tubes, various spacers or agitators located inside of the tubes, or other means such as exceptional- ;ly high velocities of the fluid created by virtue of ,certain arrangement of serpentine flow. All of .such devices are intended to create a higher rate of heat transfer. However, most of such devices are actually only efiicient at moderate temperatures from approximately 32 Fahrenheit and upward, but are extremely inefficient when subjected to act in their created capacity when the same are exposed to freezing temperatures that drop 32 below Fahrenheit. Such units have been found to congeal the oil at the low'temperatures referred to and it takes an excessive amount of pressure to finally break loose and 'al-. low the congealed oil to flow. This may only occur in certain of thetubeswhile many of the outer or less efiicient tubes from the standpoint of receiving heat to thaw out the oil may never become warm enough to allow the oil to finally break through andflow in themanner required in oil coolers particularly when subjected to a continuous streamof low temperaturedair.

Briefly then, as has been proven by practical field tests, oil coolers of the present day construction are not of sufiicient capacity and of suitable design to readily operate in their full capacity whenever such oil coolers are called into use after remaining idle in temperatures ranging from freezing to approximately 20 below zero. If the fins are of ferrous or low conductivity metal an insufficient amount of heat will be radiated or thermally conducted through the fins between the tubes to cause a breaking down of the congealed oil in many of the high capacity cooling tubes. Even in the event that copper fins are employed, while the heat conductivity is relatively high, the surfaces are also designed and arranged so as to give ahigh rate of heat transfer for the cooling function and consequently the same troubles prevail in copper fin cores wherein sufiicient heat cannot be conducted from tube to tube while a cold air blast is flowing over the fins, and therefore the oil cannot be broken through to bring the tube into service to subsequently function as a cooling instrumentality in the oil cooler core.

One of the main objects of the present invention is, therefore, to overcome the deficiencies above mentioned and to create a core or oil cooler unit which will function below freezing temperatures and possibly to approximately 20 below zero and which also remains efficient and practical for higher temperatures.

One of the other objects of the present invention is to employ a core or oil cooler unit which is made of fins that are of ferrous or low conductivity metal but which are provided with eflicient heat conducting and direct heat transfer members that will act to readily break down congealed oil in the tubes whenever the oil cooler has been standing idle in abnormally low temperatures of freezing to zero and below.

All other advantages and novel features shall hereinafter appear in the following detailed description having reference to'the accompanying drawings.

In the drawings:

Fig. 1 isa front elevational view of a section of core of 'an oil cooler illustrating a preferred form and arrangement of the oil cooler and thermal members of the. present invention.

Fig. 2 is a plan sectional view of the core section illustrated in Fig. 1 taken substantially along the line 22 in Fig. 1.

Fig. 3 is another plan section simulating Fig. 2 but illustrating another arrangement of the heat conducting thermal members in contrast with that illustrated in Fig. 2.

Fig. 4 is a fragmentary plan sectional view also illustrating another arrangement of heat conducting members such as may be employed in following the teachings of the present invention.

Fig. 5 is a front elevational view of another modified form of core section.

Fig. 6 is a plan sectional view taken substantially along the line 6-6 of Fig. 5.

Fig. '7 is a plan sectional view of the same core section shown in Fig. 5 but illustrating a modified arrangement of the heat conducting thermal members as applied thereto.

Fig. 8 is still another form of core section as viewed in front elevation; and

Fig. 9 is a plan sectional view taken substantially along the line 9-9 in Fig. 8.

Referring to Figs. 1 and 2, a preferred form of core section is indicated with a plurality of tubes IE! which may be interspersed with one or more tubes I I arranged at intervals between the tubes II). In this form of construction, the tubes I53 may be of the usual size and cross-sectional area or of any standard size while tubes such as I I are over-sized with respect to the former for the purpose of reducing friction and to permit the free flow of fluid such as oil therethrough and under abnormally cold conditions and under the usual range of pressures normally employed in oil coolers.

All of the tubes in Figs. 1 and 2 are suitably connected and disposed in spaced relation by conventional fins of any well known form or construction and in the present case such fins are straight as shown and designated by the reference numeral I2. As hereinbefore referred to the fins may be constructed of steel, Monel metal or Cupro nickel or of any other ferrous material of low thermal conductivity metal for the purpose of strengthening the core structure of the oil cooler; and the tubes I0 and II may or may not be of such metal and are preferably of copper. The fins can also be made of copper whenever conditions permit.

In addition to the tubes It and I I and the fins I2, the present invention proposes and very efficiently incorporates the use of copper wire connectors such as I that act as heat conducting members which are so incorporated in the core as to substantially offer no additional resistances to the free flow of the air therethrough. These copper wires I4 are conveniently connected between the free flowing oil tubes I I of larger crosssectional area which will naturally receive a considerable amount of heat from the oil as the latter starts to flow therethrough, and the wires extend to the other tubes of lesser cross-sectional area and in which the oil would normally be congealed during the early warm-up stage of the oil cooler. The wires I4 may be brazed or soldered or secured in any manner desirable and are also secured to the fins I2 thereby to further expedite the transfer of heat between the large warm or hot tube II and the smaller tubes I 0. Inasmuch as the wire forms a shielding means or a small wind break for a limited portion of the fin, the latter shielded section of said fin will also then act as a collateral instrumentality as a further convenient and efficient way of transferring and dissipating heat between the tubes in the manner mentioned. Furthermore the heat conducting wires are exposed to the cooling medium passing over the fins.

Obviously, the wires I 4 may be of any other relatively high heat conductivity metal and may or may not be in the form of wires. The thermal conductivity members can also be made, if preierred, as metal bars or bands or in any other form or shape applicable to the particular situation and arrangement of elements.

In Fig. 3, the general core construction remains substantially the same as in Figs. 1 and 2 with the exception that the wires I4 are now supplanted by a modified arrangement and grouping of wires such as at I5 which are adapted to act and function for the same purpose as hereinbefore stated. In Fig. 3, the wires I 5 radiate or expand in pairs from the central enlarged tube I I to the peripherally grouped tubes ID. A modification of this arrangement is illustrated in Fig. 4 wherein wires I6 are employed, and wherein the ends of two wires extend laterally from the center enlarged tube to the laterally disposed side tubes Iii in the same manner as in Fig. 3 but wherein the other ends of the wires I6 are first directed to the outermost corner tubes for the sake of better conductivity and a greater amount of heat transfer to such tubes, and wherein the ends I? of the wires it are then turned inwardly to meet the intermediate tubes Iii at opposite sides thereof. In this manner the wire ends terminate on each side of one remote tube instead of having one wire terminate on one tube alone as in Fig. 3. This would afiord a better controlled and guided heat distribution for the purpose of thawing out the corner tubes or such other tubes that are more remotely located with respect to the central region of the core.

By arranging the wires I6 in the manner shown in Fig. 4, a certain shielded or dead air space is theoretically formed upon the fin I2 that may be designated generally as I8 in Fig. 4. This area simulates the shielded areas 49 and 26 which are so created by the looped wires I4 in Fig. 2. This affords the additional advantage of having a segregated portion of certain fins shielded more or less by encompassing wires or wire. This shielded fin area, for all practical purposes, will receive somewhat less cooling air and will therefore act to become a more efficient and better heat conducting pathway or surface to further aid the thermal members in thawing out the outlying tubes with respect to the other and over-sized free flowing tubes such as I I.

In Figs. 5 to 7 inclusive, the core structures are primarily such as to be directed to the use of tubes such as Ii] that may all be of a standard size but which are divided into smaller heat conducting passages by means of thin longitudinal members such as the vanes or dividers 22 best illustrated in Figs. 6 and 7. The vanes or dividers 22 are associated with certain tubes 23 that actually are of the same cross-sectional area and outline as tubes Ill. By the addition of the vanes we have arrived at the same results that prevail in the use of over-sized tubes II in combination with the smaller size tubes I0. The only difference in Figs. 5 to '7 inclusive is that all of the tubes are of the same external size with the exception that tubes IE remain free and open and are equivalent to the over-sized tube II of Figs. 2 to 4, while the tubes 23 carrying the vanes or dividers 22, imulate the tubes Ii] in the sense that they contain more restricted and narrower passageways.

In Figs. 5 and 6, the heat transfer elements are composed of relatively short wires 24 that transgress the lateral space between the sets or rows of tubes to form the conducting members for transferring the heat from the open tubes to the divided tubes 23.

In Fig. 7, the wires 24 have been supplanted by means of the straight wires 25 to function in the same capacity, namely, as solid thermal conducting members. The Wires 25 are disposed to flank the tubes Ill and 23 so as to extend in the line of the normal flow of air through the core section.

The oil cooling core structure shown in Figs. 8 and 9 is essentially an outcrop of several of the foregoing forms and includes a plurality of tubes 23 having the dividers 22 inserted therein, which tubes are interspersed with one or more oversized tubes such as H. In this core as in the cores of Figs. 1 and 5, the usual and conventional type of fins l2 are employed for cooling the tubes. However, certain of the fins l2 are supplanted by means of the heavier and. more efficient heat conducting fins 26 for the purpose of functioning as the thermal conducting members for transferring and dissipating a more generous amount of heat from the enlarged and oversized tubes l to the smaller and more restricted tubes 23 during the warm-up stages at the beginning of the operation of the oil cooler. The fins 2B in Figs. 8 and 9 are preferably of heavy copper or of other high heat conductivity metal.

From the foregoing description relating to the various forms and modifications of means for creating an efiicient equalization of heat dissipation during the early stages of the warm-up period of the oil cooler, it should be noted that the main principle predominant in the description and'disclosure relates to the use of a wire or any other formed piece of metal of comparatively large cross-sectional area and which wire or formed piece of metal possesses a low or reasonably small exposed surface that is not readily afiected by the air fiow through the oil cooler core. The sole function of this wire or formed piece of metal or heavy fin as in the case of Figs. 8 and 9 is to transmit heat from the large tubes to the small high cooling capacity tubes for the purpose of breaking down the congealed oil and to quickly place these tubes into service for the purpose 'of subsequently cooling said oil. The same wire or formed piece of metal also acts in the dual capacity of subsequently preventing the congealing of oil in the small high cooling capacity tubes whenever said core is subjected to continual cold air blasts of abnormally low temperatures.

As is obvious from the description and the disclosures in the drawings, the principal features of the present invention may be adapted to numerous modifications which are ultimately applicable to produce the same fundamental results and to carry out the purpose herein related. For this reason the present invention is not to be limited to the exact description or identical disclosures excepting insofar as shall be determined by the breadth and scope of the appended claims.

What I claim as new and desire to secure by Letters Patent is:

1. A core for liquid coolers comprising a plurality of liquid cooling tubes, some with relativel small liquid passageways and certain others hav ing comparatively large liquid passageways, cooling fins traversing said tubes, and heat conduct ing members for thermally connecting a tube having a large liquid passageway with a plurality of tubes having smaller liquid passageways to provide heat transfer and equalizing heat dissipation units, said heat conducting members comprising wires of comparatively large cross-sectional areas with relatively small exposed surface areas and having a greater coefiicient of heat conductivity than the fins.

2. A core for liquid coolers comprising a plurality of liquid cooling tubes, some with relatively small liquid passageways and certain others having comparatively large liquid passageways, cooling fins traversing said tubes, and heat conducting members bonded to the tubes and adapted for thermally connecting a tube having a comparatively large liquid passageway with a plurality of tubes having relatively small passageways to provide heat transfer and equalizing heat dissipation wires, said heat conducting members comprising solid wires composed of a material of higher heat conductivity characteristics compared to said cooling fins.

3. A heating conducting means in a core of a liquid cooler having tubes and fins, comprising a solid heat conducting member exposed to a cooling medium passing over said fins, said heat conducting member being of relatively large cross sectional area and relatively small surface area and carried between and bonded to certain tubes and secured contiguous with a fin, said member being of higher heat conductivity than said fin and providing a definite pathway for directed heat dissipation between tubes, said portion of said fin immediately adjacent said heat conducting member also coacting with said member to increase said heat dissipation along the direction of said member.

4. A core for a liquid cooler comprising a tube having a large passageway, a plurality of tubes having relatively smaller passageways, cooling fins connecting all of said tubes, and a heat conducting copper wire bonded to the tube having the large passageway and to the plurality of tubes having the relatively small passageways and serving to conduct heat from the first named tube to the others during the warming up stage, and the fins serving to prevent overheating of the tubes.

CHARLES T. PERKINS. 

